The object of the proposed research is the determination of the synaptic mechanisms and functional interconnections used in the vertebrate retina to process visual information. Of particular interest are the relationships between the mechanisms controlling retinal sensitivity during light and dark adaptation; changes in spatial and temporal interactions as related to adaptation; the sites of rod saturation. These objectives will be approached by recording ganglion cell discharges from the optic nerve fibers of the skate and the rat with metal microelectrodes and by means of intracellular recordings in the skate retina.